A tool to tackle the Challenges of the Treatment of the Back Produced Viscosified Water

When the Enhanced Oil Recovery process involves a polymer injection (P, and/or SP), both surfactants and polymer are expected to be produced with production fluid, at different ratio along field life. This means changes of miscibility of fluids versus time, leading to some challenges with regard to the process and its flexibility against time. Depending on the start up of the EOR production through field life, more water treatment difficulties would have to be managed comparing to separation issues; otherwise the efficiency of both water treatment and separation could be partially lost. This paper is focusing on water treatment technologies assessment regarding inlet characteristics of produced water in presence of HPAM polymer back production. Technologies to be tested have been chosen to tackle expected thinner oil droplets in water emulsion. To answer the request of high quality of water (oil and solids contents targets) for re-injection, water technologies like filtration and centrifugation have been assessed through lab bench screening. Results are variable depending on technologies and severity of inlet conditions but they look promising. A pilot scale has been designed, a platform of tests has been built to help projects better design their process and subsidiaries optimize existing processes. This platform supplies viscosified water with degraded polymer to mimic field conditions, which is mixed with oil and solids to generate actual field produced water. This recombined back produced viscosified water feeds the open loop for the testing of various water treatment equipments. Oil droplet size is controlled on line as well as oil content. The scale of this platform allows screening of a rather large range of characteristics of back produced water in terms of oil droplet size, polymer content and viscosity, in order to qualify a suitable technology for a given range of operability.